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(11) | EP 0 434 034 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Oxazole derivatives |
| (57) Oxazole derviatives having Formula I or II are disclosed which are useful as inhibitors
of mammalian blood platelet aggregation.
Formula I and Formula XIX compounds are those wherein n is 7-9 and R is hydrogen or lower alkyl. Formula II compounds are those wherein R is hydrogen, lower alkyl or together with C02 is tetrazol-1-yl; R1 is phenyl or thienyl; X is a divalent connecting group selected from the group consisting of CH2CH2, CH = CH, and CH20; Y is a divalent connecting group attached to the 3 or 4 phenyl position selected from the group consisting of OCH2, CH2CH2 and CH=CH. Formula XX compounds are those wherein the OCH2C02R moiety is attached to the 3 or 4 phenyl position and R is hydrogen or lower alkyl. |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of pending application U.S. Serial No. 07/453,548 filed December 20, 1989.
BACKGROUND OF THE INVENTION
[0002] This invention generally pertains to heterocyclic carbon compounds having drug and bio-affecting properties and to their preparation and use. In particular, the invention is concerned with oxazole derivatives characterized by Formulas I and II, infra., which are inhibitors of blood platelet aggregation.
[0003] The following chemical literature and patents are illustrative of related oxazole prior art known to applicant.
[0004] D. L. Aldous, et al., J. Org. Chem., 25, 1151 (1960) describe the chemistry of styryloxazoles of the formula
wherein R is hydrogen, p-methoxy, o-hydroxy and 3,4-methylendioxy.
[0005] Brown, U.S. Patent 3,578,671 describes a class of oxazole-2-polycarbon aliphatic monocarboxylic acids arylated at the 4- and/or 5-position in the oxazole ring of the formula
in which each of the substituents R2 and R3 is a member of the group consisting of unsubstituted phenyl, naphthyl, thienyl and furyl radicals and phenyl radicals substituted by substituents selected from the group consisting of halogen, lower alkyl, lower alkoxy, nitro and trifluoromethyl radicals; and wherein R1 is selected from the group consisting of carboxyalkyl- and carboxylalkenyl radicals each containing from 2 to 5 carbon atoms and the amides, hydroxamic acid derivatives, lower alkyl esters and lower alkanoyloxy-lower-alkyl esters thereof. The compounds of U.S. 3,578,671 include the clinically effective anti-inflammatory agent known generically as oxaprozin (R2 = R3 = phenyl, R1 = (CH2)2C02H).
[0006] Meanwell, et al., U.S. Patent 4,775,674 describe a series of 2,3-dihydro-2-oxo-1H-imidazo[4,5-b]-quinolinyl ether derivatives of the formula
wherein inter alia R1 and R2 are hydrogen, and "alk-Y" an alkanoic acid and ester residue. The compounds of U.S. Patent 4,701,459 have cyclic AMP phosphodiesterase inhibitor activity and are useful as inhibitors of blood platelet aggregation and/or as cardiotonic agents.
[0007] Lautenschlager, et al., U.S. Patent 4,460,598 issued July 17, 1984 describe a series of triphenylimidazol-2-yloxyalkanoic acids having the formula
wherein R1, R2, R3, R4, R5 and R6 each are H, halogen, alkyl, alkoxy and trifluoromethyl; n is an integer of 1 to 10 and R7 is H, alkali metal ions, alkyl or benzyl group. The compounds of U.S. Patent 4,460,598 are reportedly useful in the treatment of thromboembolic, inflammatory and/or atherosclerotic disease in man. A particularly preferred member of the series wherein R1 to R6 is hydrogen, n is 7 and R7 is sodium (identified in the art as octimibate sodium) has been described as possessing anti-aggregator activity and is under clinical development as an antihyperlipidemic agent.
SUMMARY OF THE INVENTION
[0008] In its broadest aspect, this invention is concerned with oxazole derivatives having Formula I and Formula II
wherein R, R1, R2, X, Y, and n are defined below which are inhibitors of adenosine diphosphate and collagen-induced aggregation of human platelet-rich plasma and are particularly useful as inhibitors of mammalian blood platelet aggregation.
[0009] Another embodiment of the invention relates to the alkali metal salts of carboxylic acids of Formula I (R is hydrogen) and Formula II (R2 is hydrogen). A further embodiment concerns pharmaceutical compositions comprised of a Formula I or II compound combined with at least one pharmaceutically acceptable excipient. Yet another embodiment relates to a method for inhibiting blood platelet aggregation in a mammal which comprises administering a therapeutically effective amount'of a compound of Formula I or an alkali metal salt thereof where R is hydrogen or a Formula II compound or an alkali metal salt thereof where R2 is hydrogen to a mammal in need of such treatment.
DETAILED DESCRIPTION OF THE INVENTION
[0010] This invention relates to inhibitors of mammalian blood platelet aggregation OF Formula I
wherein n is 7-9 and R2 is hydrogen or lower alkyl; or when R is hydrogen, the alkali metal salt thereof.
[0011] The compounds of the instant invention are further characterized by Formula II
wherein
R1 is-phenyl or thienyl;
R2 is hydrogen, lower alkyl or together with CO2 is tetrazol-I-yl;
X is a divalent connecting group selected from the group consisting of CH2CHz, CH=CH, and CH20;
Y is a divalent connecting group attached to the 3-or 4-phenyl position selected from the group consisting of OCH2, CH2CH2 and CH=CH,
or when R2 is hydrogen, an alkali metal salt thereof.
[0013] The term "lower alkyl" refers to a branched or unbranched saturated hydrocarbon chain containing from 1-4 carbon atoms; specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, secondary butyl, and tertiary butyl.
[0014] The term "lower alkanol" denotes an alcohol having 1-4 carbon atoms defined by "lower alkyl".
[0016] The term "alkali metal salts" comprehends the alkali metals and most preferably sodium and potassium.
[0017] When the "divalent connecting group X is CHzO", carbon is covalently bonded to the oxazole and oxygen is covalently bonded to the substituted phenyl grouping.
[0018] When the "divalent connecting group Y is OCH2", oxygen is covalently bonded to phenyl and carbon is covalently bonded to the carboxylic function.
[0019] According to the present invention, the compounds characterized by Formula I, as defined above, are obtained by a process comprising:
(a) hydrolyzing a compound of Formula la
wherein n is 7-9 and Ra is lower alkyl to the corresponding acid, or
(b) esterifying a compound of Formula lb
wherein n is 7-9 with a lower alkanol, or
(c) reacting a keto ester of Formula III
wherein n is 7-9 and R is hydrogen or lower alkyl with ammonium acetate to form the
corresponding oxazole, or
(d) decarboxylating a substituted malonic acid of Formula IV
wherein n is 6-8.
Scheme 1 below illustrates the foregoing process.
[0020] In general, oxazole ring formation is conventionally accomplished by treating a keto ester with an excess of ammonium acetate in acetic acid at reflux temperature. The keto esters (IIIa,b,c) are obtained by esterifying benzoin with an appropriately substituted carboxylic acid. For example, keto ester (Ilia) is obtained by coupling benzoin (V) and the half ester of the dicarboxylic acid HO2C(CH2)nCO2Ra where n is 7-9 and Ra is lower alkyl using 1,3-dicyclohexylcarbodiimide in the presence in a catalytic amount of 4-dimethylaminopyridine according to the procedure of H. H. Wasserman, et al., Tetrahedron, 37, 4059-4064 (1981). Purification is not required and the keto ester (Illa) treated with an excess of ammonium acetate in acetic acid at reflux temperature provides oxazole (la). Hydrolysis of the ester functionality with aquous hydroxide provides the corresponding acid (lb).
[0021] Alternatively, oxazole (lb) can be prepared by treating keto ester IIIc, where n is 6-8, with ammonium acetate and acetic acid to provide the oxazole bromide intermediate (VI, n = 6-8). Treating this intermediate with a 3-fold excess of dimethylmalonate and potassium t-butoxide in tetrahydrofuran (THF) at reflux in the presence of a catalytic quantity of 18-Crown ether-6 provides the methyl ester of (IV) which is saponified to diacid (IV) and thermally decarboxylated to give (Ib). Esterification of (lb) is accomplished conventionally by heating the acid (Ib) in a lower alkanol in the presence of concentrated sulfuric acid.
[0022] Another approach to the preparation of (Ib) involves esterification of benzoin (V) with a three-fold excess of the dicarboxylic acid H02C(CH2)nC02H where n is 7-9 in the presence of a slight excess of 1,3-dicyclohexylcarbodiimide and a catalytic amount of 4-dimethylaminopyridine in methylene dichloride to provide the keto ester (Illb). Treatment of the crude keto ester (IIIb) with ammonium acetate under standard conditions affords the oxazole acid (Ib) which is separated from by-products by column chromatography.
[0023] Alkali metal salts of Formula I carboxylic acids are conventionally prepared by dissolving the acid in methanol with a molar equivalent of an alkali base such as sodium methoxide and precipitating the salt or removing the solvent.
[0024] According to the present invention, the compounds characterized by Formula II
wherein
R1 is phenyl or thienyl;
R2 is hydrogen, lower alkyl or together with C02 is tetrazol-I-yl;
X is a divalent connecting group selected from the group consisting of CH2CH2, CH=CH and CH20; and
Y is a divalent connecting group selected from the group consisting of OCH2, CH2CH2 and CH=CH are obtained by a process comprising:
(a) hydrolyzing a compound of Formula IIa
wherein R2a is lower alkyl and Ri, X and Y are as defined above to the corresponding acid; or
(b) esterifying a compound of Formula (Ilb)
wherein R1, X and Y are as defined above with a lower alkanol; or
(c) reducing a compound of Formula (III)
wherein R1, R2 and Y are as defined above to provide a compound of Formula (IV)
wherein R1, R2 and Y are as defined above,
(d) alkylating a compound of Formula (V)
wherein R1 and X are as defined above and OH is attached to the 3 or 4 phenyl position with
BrCH2C02R2 wherein R2a is lower alkyl to provide a compound of Formula (VI)
wherein R2a is lower alkyl, R1 is as defined above, and X is CH2H2, CH = CH; or
(e) alkylating a 3 or 4 substituted phenyl of Formula (VII)
wherein Ya is CH20 or CH2CH2 and R2a is lower alkyl with an oxazole of Formula (VIII)
wherein R1 is phenyl or thienyl to provide a compound of Formula (IX)
wherein R1 and R2 are as defined above and Ya is CH20 or CH2CH2,
(f) reacting the trifluoromethanesulfonate ester of a compound of Formula (X)
wherein R1 is phenyl or thienyl and OH is attached to the 3 or 4 phenyl position with H2C=CHCO2R2a wherein R2a is lower alkyl to provide a compound of Formula (XI)
wherein R1 is phenyl or thienyl and R2a is lower alkyl,
(g) reacting a compound of Formula (XII)
wherein R1 is phenyl and the formyl grouping is attached to the 3 or 4 phenyl position with
the trimethylphosphonate derivative of CH2CO2R2a wherein R2a is lower alkyl to provide a compound of Formula (XIII)
wherein R1 and R2a are as defined above,
(h) reacting a compound of Formula (XIV)
wherein R2a is lower alkyl and the side chain is attached to the 3 or 4 phenyl position with
a phosphonate oxazole of Formula (XV)
wherein R1 is phenyl or thienyl to provide a compound of Formula (XVI)
wherein R1 is phenyl or thienyl and R2a is lower alkyl,
(i) treating a compound of Formula (XVII)
wherein X and Y are as defined above with tri-n-butyltin azide to provide a tetrazole
of Formula (XVIII)
wherein X and Y are as defined above.
[0025] The following schemes for preparation of representative compounds of Formula II illustrate the foregoing process.
[0026] Scheme 2 depicts preparation of Formula II compounds derived from phenylpropionic and cinnamic acids. Akylation of the sodium salt of a hydroxyphenylpropionic acid (2) or hydroxycinnamic acid (3) with desylbromide (1) followed by oxazole formation provided phenols (4) and (5) which were alkylated with an 2-bromoalkanoic acid ester to give esters (6) and (7), respectively. Subsequent hydrolysis with aqueous alkali provided the corresponding acids (8) and (9). The saturated compounds (6) and (8) were synthesized from the unsaturated precursors (7) and (9) by way of hydrogenation, preferably catalytic, which also could be carried out at the phenolic stage as shown.
[0027] Scheme 3 depicts an alternate approach to the preparation of esters (7) involving coupling of the dimethylphosphonate (11) prepared from bromide (10) via an Arbuzov reaction described by D.C. Schroeder, et al., J. Org. Chem., 27, 1098-1101 (1962) with a functionalized aldehyde (12). Proton NMR data indicated that the unsaturated compounds were predominantly, if not exclusively, of the trans configuration.
[0028] Scheme 4 depicts preparation of Formula II compounds incorporating an oxygen atom in the linkage between the aryl and oxazole rings. Bromination of 4,5-diphenyl-2-methyloxazole according to a modification of the procedure of D.L. Aldous, et al., J. Org. Chem., 25, 1151-1154 (1960) using N-bromosuccinimide in carbontetrachloride at reflux in the presence of 2,2'-azobis(2-methyl-propionitrile) provided bromide (13). Alkylating the hydroxy benzaldehyde (14) with bromide (13) in the presence of potassium carbonate in refluxing acetonitrile produced aldehyde (15) which was converted to ester (16) by way of the Wadsworth-Emmons modification of the Wittig reaction according to W.S. Wadsworth, Org. Reactions, 25, 73-253 (1978). Conventional alkaline hydrolysis of ester (16) gave carboxylic acid (17). Saturated estër (18) and acid (19) were synthesized by alkylating the ester of 3-hydroxyphenylpropionic acid (20) in the presence of potassium carbonate and subsequent hydrolysis.
[0029] Scheme 5 depicts the preparation of compounds of Formula II wherein the connecting radical Y is "CH CH" X is CH2 CH2 or CH = CH. The triflate (22) was synthesized from the oxazole phenol (21) by treatment with trifluoromethanesulfonic anhydride in pyridine. Reacting the trifluoromethanesulfonate ester (22) with ethyl acrylate in the presence of a Pd catalyst afforded cinnamic ester (23). Base-induced hydrolysis of (23) gave acid (26). Catalytic hydrogenation of the cinnamic ester (14) provided saturated ester (24) which was converted to acid (25) under aqueous alkaline conditions.
[0030] Scheme 6 illustrates the preparation of compounds of Formula II when the "X connecting group" is CH20 and the "Y-side chain connecting group" is OCH2. Resorcinol mono-acetate (27) was alkylated with methyl bromoacetate to give (28) which was dissolved in methanolic hydrogen chloride solution to provide phenol (29). Alkalation of phenol (29) with bromide (10) provided the oxazole ester (30) which was hydrolyzed to carboxylic acid (31) using aqueous hydroxide solution.
[0031] Scheme 7 illustrates the preparation of compounds of Formula II wherein the two phenyl rings are replaced by thiophene rings in the two possible regio-isomeric forms. The 2-methyl-4,5-(2- or 3-thienyl) oxazole derivatives (32) were obtained by the method of D. Davidson, et al., J. Org. Chem., 2, 328-334 (1937) from 2- or 3-thiophene carboxaldehyde. Metalation of (32) using n-butyllithium followed by benzyl bromide (33) provided oxazoles (34). The phenolic protecting group dimethyi(1,1-dimethyiethyi)siiane was removed using n-butylammonium fluoride to furnish phenols (35). Conventional alkylation with methyl bromoacetate gave esters (36) which were hydrolyzed to carboxylic acids (37) with aqueous hydroxide solution.
[0032] Scheme 8 illustrates preparation of compounds of Formula II wherein the carboxylic acid moiety is replaced with the tetrazole heterocycle. Treatment of phenol (21) with bromoacetonitrile and potassium carbonate gave nitrile (38) which was converted to the tetrazole (39) with tri-n-butyltin azide.
[0033] Alkali metal salts of Formula II carboxylic acis are conventionally prepared by dissolving the acid in a suitable solvent such as methanol, adding a molar equivalent of an alkali base such as sodium methoxide, and precipitating the salt or removing the solvent.
[0034] As stated above, the compounds of Formula I and Formula II have pharmacological properties which make them particularly useful as inhibitors of blood platelet aggregation.
[0035] Platelet aggregation is considered part of a complex physiological mechanism for formation of a thrombus in the vascular system. Thromboembolic phenomena, i.e., the formation of thrombi, are involved in hemostasis and a number of diseased states in mammals including thrombophlebitis, phlebothrombosis, cerebral thrombosis, coronary thrombosis and retinal vessel thrombosis. An increase in propensity for platelet aggregation, sometimes referred to as platelet adhesiveness, is observed following parturition, surgical operations such as coronary artery bypass surgery, organ transplant, angioplasty, prosthetic heart valve implants to name a few and in ischaemic heart disease, artherosclerosis, multiple sclerosis, intracranial tumors, thromboembolism, and hyperlipemia; refer to A. Poplawski, et al., J. Artherosclerosis Research, 8, 721 (1968). Thus, the compounds of the invention which have antithrombogenic (inhibit blood platelet aggregation) are useful in prevention or treatment of conditions involving platelet aggregation and thrombosis such as the above. The instant compounds are also considered to have antimetastatic potential in view of their platelet inhibition properties.
[0036] The pharmacological properties of the instant compounds can be demonstrated by conventional in vitro and in vivo biological tests such as the following.
IN VITRO INHIBITION OF HUMAN PLATELET AGGREGATION
[0037] The aggregometer method of Born, C.V.R., J. Physiol., (London), 1962, 162, 67-68, as modified by Mustard, J.F., et al., J. Lab. Clin. Med. 1964, 64, 548-599 was used to assess the in vitro activity of the various compounds as to the inhibition of adenosine diphosphate (ADP) and collagen-induced platelet aggregation. The human volunteer donor's arm is cleansed with 70% ethyl alcohol. A sterile 20 ml syringe and needle are used to withdraw 20 ml of blood. The blood is immediately added to a test tube containing 3.8% sodium citrate to prevent clotting (1 part citrate to 9 parts blood).
[0038] Platelet rich plasma (PRP) was separated by centrifugation for 10 minutes at 1000 rpm (140xg) from citrated (3.8%) human blood. All glassware used for preparation of PRP is silicon treated. ADP in final concentration of 0.5 mcg/mL or 0.05 mL of a collagen suspension prepared according to the method described by Evans, G., et al., J. Exp. Med., 1968, 128, 877-894 was used to induce aggregation. The various compounds tested were dissolved in dimethylsulfoxide (DMSO) so that 5 mcl added to the platelet rich plasma would yield the desired test concentration. Vehicle control trials were done and compared with aggregation induced in platelet rich plasma containing various concentrations of the test compounds. Dose response curves were obtained and Inhibitor Concentration (ICso) values calculated or the percent inhibition at 32 mcg/mL noted. In this test, the IC50 values for dipyridamole, a clinically useful antithrombogenic agent, are 512 mcg/ml vs. ADP and 245 mcg/ml vs collagen. Results are given in Tables I, II and III hereinafter for various Formula I and II compounds and related prior art compounds.
[0039] It is evident that the acids of Formula I (Examples 2 and 4) are active whereas the short chain acids of U.S. 3,578,671 are essentially inactive against ADP-induced aggregation of human platelets. As for the esters (Examples 1 and 3) corresponding to Examples 2 and 4, they are relatively weak anti-aggregators in vitro but serve as pro drugs in vivo where they are readily hydrolyzed to the active acids.
IN VIVO INHIBITION OF BIOLASER INDUCED THROMBOSIS
[0040] The laser induced thrombosis method is a modification of the technique developed by Sanders, A.G., et al. in Brit. J. Exp. Pathol., 1954, 35, 331 and Grant, L., et al. in Proc. Soc. Exp. Biol. Med., 1965, 119, 1123. A detailed description of this method has been described by Fleming, J.S., et al. in Platelets and Thrombosis, A. Scriabine and S. Sherry, eds., Baltimore, Univ. Park Press, pp. 247-262, 1974 and is hereby incorporated by reference.
[0041] Briefly, Lucite ear chambers were chronically implanted in adult, English lop-ear rabbits. The animals were conditioned to lie quietly in the supine position. Localized microvascular injury was induced by focusing a single ruby laser beam through a microscope into the lumen of a vessel 10-60 mcM in diameter. This evoked the formation of a small thrombus consisting of platelets accumulated around a core of one or two damaged red cells. Thrombus area was determined as a product of two perpendicular measurements made by using a micrometer eye piece. The mean thrombus area (mcM2) obtained for 10 trials in each rabbit served as a control value. The test compound was administered orally and post-dose trials were performed at selected times. Pharmacological activity was evaluated by comparing pre- and post-dose mean thrombus areas.
[0042] In the above biolaser model of thrombosis, the compound of Example 6 exhibited 53% inhibition of thrombosis at an oral dose of 10 mg/kg, 38% inhibition at 3 mg/kg and 23% inhibition at 1 mg/kg body weight.
[0043] The dosage employed in the therapeutic methods of the instant invention will vary with the form of administration, the particular compound chosen, the subject being tested and the effect desired. Suitable effective doses in animals range from 0.1-50 mg/kg body weight orally and from 0.05-10 mg/kg body weight parenterally (generally characterized as subcutaneous, intramuscular, and intravenous injection). It is contemplated that the effective unit dose in man will range from 1 to 100 mg and preferably from 0.5 to 20 mg administered one to three times a day. In accordance with conventional clinical practice, the effective dose can be determinted by administering a Formula I or II compound at a dosage substantially less than the dose of the compound which is thought to be effective and then increasing the dosage in small increments until the desired effect is achieved.
[0044] In carrying out the instant therapeutic methods, the active ingredient of Formula I or II or alkali metal salts of Formula I and Il] carboxylic acids are preferably administered with a pharmaceutically acceptable carrier and such compositions constitute part of the instant invention. Suitable dosage forms for oral use are tablets, dispersible powders, granules, capsules, syrups and elixirs. Examples of parenteral forms are solutions, suspension, dispersions, emulsions, and the like. The compositions for oral use may contain one or more conventional adjuvants, such as sweeetening agents, flavoring agents, coloring agents and preserving agents, in order to provide a composition of suitable pharmaceutical elegance. Tablets may contain the active ingredient in admixture with conventional pharmaceutical acceptable excipients including indert diluents such as calcium carbonate, sodium carbonate, lactose and talc; granulating and disintegrating agents such as starch and alginic acid; binding agents such as starch, gelatin and acacia and lubricating agents such as magnesium stearate, stearic acid and talc. The tablets may be uncoated or coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. Similarly, suspension, syrups and elixirs may contain the active ingredient in admixture with any of the conventional excipients utilized for the preparation of such compositions such as suspending agents (e.g., methylcellulose, tragacanth, and sodium alginate), wetting agents (e.g., lecithin, polyoxyethylene stearate) and preservatives such as ethyl-p-hydroxybenzoate. Capsules may contain the active ingredient alone or admixed with an inert solid diluent such as calcium carbonate, calcium phosphate and kaolin. The injectible compositions are formulted as known in the art and may contain appropriate dispersing or wetting agents and suspending agents identical or similar to those mentioned above.
[0045] The following examples are given by way of illustration and are not to be construed as limiting the invention in any way inasmuch as many variations of the invention are possible within the spirit of the invention.
DESCRIPTION OF SPECIFIC EMBODIMENTS
[0046] In the following examples, all temperatures are given in degrees Centigrade. Melting points were recorded on a Thomas-Hoover capillar melting point apparatus and are uncorrected. Proton magnetic resonance ('H-NMR) spectra were recorded on a Bruker AM 300, Bruker WM 360 or Varian Gemini spectrometer. All spectra were determined in CDC13 or DMSO-d6 unless otherwise indicated and chemical shifts are reported in delta units downfield from the internal standard tetramethylsilane (TMS) and interproton coupling constants are reported in Hertz (Hz). Splitting patterns are designated as follows: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; br, broad peak; and dd, doublet of doublet.
EXAMPLE 1
Methyl 4,5-diphenyl-2-oxazolenonanoate
[0048] A mixture of 4,5-diphenyl-2-oxazole nonanoic acid (800mg, 2mmol), methanol (20mL) and concentrated sulfuric acid (2 drops) was heated to reflux. After 2 hours, the solvent was evaporated and the residue partitioned between CH2CI2 and water. The organic phase was separated, washed with saturated NaHC03 solution, dried over sodium sulfate and concentrated in vacuo to leave an oil. Chromatography on a column of silica gel using a mixture of hexanes and diethyl ether (4:1) as eluent gave methyl 4,5-diphenyl-2-oxazolenonanoate (800 mg, 96%).
[0049] Anal. Calcd. for C25 H29 N03: C, 76.70; H, 7.47; N, 3.58. Found: C, 76.61; H, 7.84; N, 3.94%.
[0050] 1H-NMR (CDCl3) delta: 1.20 to 1.50 (8H, m), 1.64 (2H, quintet, J = 7Hz), 1.87 (2H, quintet, J = 7Hz), 2.32 (2H, t, J = 7.5Hz), 2.87 (2H, t, J = 7.5Hz), 3.67 (3H, s), 7.20 to 7.50 (6H, m) and 7.60 to 7.80 (4H, m).
EXAMPLE 2
4,5-Diphenyl-2-oxazolenonanoic Acid
[0052] 2-[7-(4,5-Diphenyl-1-oxazolyl)heptyl]propanedioic acid (4.50g, 10mmol) was heated with stirring at 150 C. After 2 hours, the flask was cooled and the residue triturated with a mixture of hexane and diethyl ether (1:1) to give a white solid. Crystallization from aqueous isopropyl alcohol afforded 4,5-diphenyl-2-oxazolenonanoic acid (3.15g, 87%) m.p. 83-85° C.
[0054] 1H-NMR (DMSO-d6) delta: 1.10 to 1.40 (8H, m), 1.46 (2H, m), 1.71 (2H, m), 2.15 (2H, t, J=7Hz), 2.76 (2H, t, J = 7Hz), 7.90 to 7.45 (6H, m), 7.45 to 7.65 (4H, m) and 11.99 (1 H, bs).
EXAMPLE 3
Methyl 4,5-diphenyl-2-oxazoleoctanoate
[0056] A mixture of benzoin (6.00g, 28mmol), azelaic acid monomethyl ester (7.17g of 92% pure material, 32mmol), 1,3-dicyclohexylcarbodiimide (7.00g, 34mmol), 4-dimethylaminopyridine (catalytic amount) and dichloromethane (120mL) was stirred at room temperature. After 16 hours, the mixture was filtered and the solvent evaporated. Ammonium acetate (10.90g, 141mmol) and acetic acid (150mL) were added to the residue and the mixture heated at reflux for 65 minutes before being cooled and diluted with water. The mixture was extracted with diethyl ether, the combined extracts dried over sodium sulfate and concentrated in vacuo. The residual oil was chromatographed on a column of silica gel using a mixture of hexanes and diethyl ether (7:3) as eluent to give methyl 4,5-diphenyl-2-oxazoleoctanoate (8.24g, 77%) as an oil.
[0058] 1H-NMR (CDCl3) delta: 1.10 to 1.35 (6H, m), 1.45 (2H, quintet, J=7Hz), 1.67 (2H, quintet, J=7Hz), 2.12 (2H, t, J = 7.5Hz), 2.66 (2H, t, J = 7.5Hz), 3.47 (3H, s), 7.05 to 7.25 (6H, m), and 7.35 to 7.55 (4H, m).
EXAMPLE 4
4,5-Diphenyl-2-oxazoleoctanoic Acid
[0060] A mixture of methyl 4,5-diphenyl-2-oxazoleoctanoate (7.00g, 18.5 mmol), 5N sodium hydroxide solution (7.42mL), water (100mL) and methanol (20mL) was heated on a steam bath for 45 minutes. After stirring at room temperature for 75 minutes, the mixture was diluted with water (150mL), heated on a steam bath for 10 minutes and then allowed to stir overnight at room temperature. The mixture was heated to reflux for 1 hour, cooled, acidified with 2N hydrochloric acid solution and extracted with CH2CI2. The combined extracts were dried over sodium sulfate and concentrated in vacuo to give an oil that crystallized. Recrystallization from a mixture of diethyl ether, CH2CI2 and hexanes furnished 4,5-diphenyl-2-ozazoleoctanoic acid (5.25g, 77%), m.p. 70-73 C.
[0062] 1H-NMR (CDCl3) delta: 1.20 to 1.45 (6H, m), 1.54 (2H, quintet, J=7Hz), 1.75 (2H, quintet, J=7Hz), 2.23 (2H, t, J = 7.5Hz), 2.76 (2H, t, J = 7.5Hz), 7.10 to 7.35 (6H, m), 7.40 to 7.60 (4H, m) and 11.74 (1 H, bs).
EXAMPLE 5
Methyl 2-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetate
[0064] A mixture of 3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenol (3.41g, 10mmol), potassium carbonate (1.52g, 11mmol), potassium iodide (catalytic amount), methyl bromoacetate (1.68g, llmmol) and acetonitrile (32mL) was stirred at reflux under an atmosphere of nitrogen. After 90 minutes, the mixture was cooled, filtered and concentrated to leave an oil which was subjected to chromatography on a column of silica gel. Elution with a mixture of hexanes, ethyl acetate and triethylamine (75:25:1) afforded methyl 2-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetate (3.59g, 86%) as a viscous oil.
[0066] 1H-NMR (CDCl3) delta: 3.14 (4H, s), 3.76 (3H, s), 4.60 (2H, s), 6.75 (1H, dd, J=8Hz, J'=2.5Hz), 6.90 (1 H, d, J=8Hz), 7.15 to 7.40 (7H, m) and 7.50 to 7.75 (4H, m).
EXAMPLE 6
2-[3-[2-(4,5-Diphenyl-2-oxazolyl)ethyl]phenoxy]acetic Acid
[0068] A mixture of methyl 2-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetate (2.25g, 5.5mmol), 3N sodium hydroxide solution (5.5mL) and methanol (50mL) was heated to reflux on a steam bath. After 5 minutes, the mixture was cooled, the methanol evaporated and the residue diluted with water. Warming provided a solution which was diluted with 1 N hydrochloric acid solution to pH 3 to give an oily precipitate. The mixture was extracted with CH2Cl2 and the organic extracts washed twice with water and once with saturated sodium chloride solution. Concentration, after drying over sodium sulfate, left a pale yellow solid which was recrystallized twice from a mixture of hexanes and CH2CI2 (2:1) to give 2-[3-[2-(4,5-diphenyl-2-oxazolyl)-ethyl]phenoxy]acetic acid (1.74g, 80%), m.p. 153.3-154.5° C.
[0070] 1H-NMR (DMSO-d6) delta: 3.12 (4H, m), 4.64 (2H, s), 6.73 (1H, dd, J=8Hz, J'=2Hz), 6.88 (2H, m), 7.20 (1 H, t, J = 8Hz), 7.30 to 7.50 (6H, m), and 12.98 (1 H, bs).
[0071] Sodium metal (0.58 g, 25 mg/atom) was dissolved in methanol (10mL) and 1mL of this solution diluted with methanol (20mL). 2-[3-[2-(4,5-Diphenyl-2-oxazolyl]ethyl]phenoxy]acetic acid (100g, 2.5 mmol) was added and the mixture stirred at room temperature for 18 hours. Evaporation of the solvent left a beige solid, sodium 2-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetate (1.06g, 100%) m.p. 278-280 C.
[0072] Anal. Calcd. for C25H20NO4Na.0.2H2O: C, 70.65; H, 4.84; N, 3.30; H20, 0.85. Found: C, 70.46; H, 4.75; N, 3.23; H20, 0.68%.
[0073] 1H-NMR (D20) delta: 2.55 (4H, bs), 4.19 (2H, s), 6.20 (1 H, d, J=7.5Hz), 6.45 to 6.70 (5H, m), 6.79 (1 H, t, J=7.5Hz), 6.90 to 7.30 (7H, m).
EXAMPLE 7
Methyl 2-[4-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetate
[0075] A mixture of 4-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenol (6.00g, 17mmol), methyl bromoacetate (2.96g, 1.83 mL, 19mmol), potassium carbonate (2.91g, 21mmol), potassium iodide (catalyic amount) and acetonitrile (80mL) was stirred at reflux. After 1 hour, the mixture was cooled, filtered and the solvent removed to leave a crystalline solid that was tritrated with hexanes and filtered to give methyl 2-[4-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetate (7.27g, 100%). An analytical sample was obtained by recrystallizing a 2.25g batch from methanol to give 1.70g of pure material which had m.p. 122-125° C.
[0077] 1H-NMR (CDCl3) delta: 3.11 (4H, s), 3.77 (3H, s), 4.60 (2H, s), 6.84 (2H, d, J=8.5Hz), 7.18 (2H, d, J = 8.5Hz), 7.20 to 7.50 (6H, m), and 7.60 to 7.80 (4H, m).
EXAMPLE 8
2-[4-[2-(4,5-Diphenyl-2-oxazolyl)-ethyl]phenoxy]acetic Acid
[0079] A mixture of methyl 2-[4-[2-(4,5-diphenyl-2-oxazolyl]ethyl]phenoxy]acetate (5g, 12mmold), 5N sodium hydroxide solution (7.26mL) and methanol (100mL) was heated on a steam bath for 45 minutes. The solution was concentrated in vacuo diluted with water and 2N HCI solution an a white solid filtered off. Recrystallization from methanol gave 2-[4-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetic acid (2.88g, 59%), m.p. 147-149 °C.
[0081] 1H-NMR (DMSO-d6) delta: 3.11 (4H, bs), 4.68 (2H, S), 6.90 (2H, bs), 7.24 (2H, d, J=6Hz), 7.30 to 7.90 (10H, m) and 13.10(1H,bs).
EXAMPLE 9
Ethyl 3-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenyl-2-propenoate
[0083] A mixture of 3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenyltrifluoromethane sulfonate (11.8g, 25mmol), ethyl acrylate (5.01g, 50mmol), triethylamine (10.12g, 100mmol) palladium II acetate (0.28g, 1.25mmol) 1,3-bis-(diphenylphosphine)propane (0.52g, 1.25mmol) and DMF (100mL) was stirred at 90°C under an atmosphere of nitrogen. After 2 hours and 6 hours additional palladium II acetate (0.28g, 1.25mmol) and 1,3- bis-(diphenylphosphine)propane (0.52g, 1.25mmol) was added. After 22 hours, the mixture was diluted with water and extracted with ethyl acetate. The combined extracts were washed three times with water and once with saturated sodium chloride solution, dried over sodium sulfate and concentrated. The residual oil was chromatographed on a column of silica gel using a mixture of hexanes and ethyl acetate (3:1) as eluent to give ethyl 3-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenyl-2-propenoate (9.37g, 88%) as an oil.
[0085] 1H-NMR (CDCIa) delta: 1.31 (3H, t, J=7Hz), 3.17 (4H, m), 4.24 (2H, q, J=7Hz), 6.41 (1H, d, J=16Hz), 7.20 to 7.50 (10H, m) and 7.50 to 7.80 (5H, m).
EXAMPLE 10
3-[3-[2-(4,5-Diphenyl-2-oxazolyl)ethyl] phenyl]-2-propenoic acid hydrate hexane solvate
[0087] A mixture of ethyl 3-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenyl]-2-propenoate (1.50g, 3.5mmol), 3N sodium hydroxide solution (3.5mL) and methanol (100mL) was heated on a steam bath. After 25 minutes the mixture was cooled, concentrated, diluted with water and made pH = 1 with dilute hydrochloric acid solution. The mixture was extracted three times with CH2CI2. The combined extracts were washed with saturated NaCI solution, dried over sodium sulfate and the solvent evaporated. The residual oil was chromatographed on a column of silica gel using a mixture of chloroform and methanol (9:1) as eluent to give 3-[3-[2-(4,5-diphenyl-20xazolyl)ethyl]phenyl]-2-propenoic acid (1.40g, 100%) as the hydrated hexane solvate after recrystallization from a mixture of hexanes and CH2Cl2 (3:1), mp 114-115* C.
[0088] Anal. Calcd. for C26H21NO3.0.6C6H14 0.2H2O: C, 78.88; H, 6.67; N, 3.11; H20, 0.70. Found: C, 78.54; N, 6.86;N,3.04; H20, 0.21 %. 1H-NMR (CDCIa) delta: 0.86 (3H, t, J=7Hz), 1.25 (4H, m), 3.19 (4H, s) 6.44 (1 H, d, J=16Hz), 7.25 to 7.70 (14H, m) and 7.75 (1 H, d, J = 16Hz).
EXAMPLE 11
Ethyl 3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]benzenepropanoate
[0090] A solution of ethyl 3-[2-(4,5-diphenyl-20xazolyl)ethyl]phenyl-2-propenoate (1.02g, 2.4mmol) in ethyl acetate (50mL) was hydrogenated over 10% palladium on charcoal (0.06g) at 35 psi. After 27 hours, the mixture was filtered, concentrated and the residue subjected to chromatography on a column of silica gel using a mixture of ethyl acetate and hexanes (9:1) as eluent. Elution gave ethyl 3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]benzene propanoate (0.92g, 90%) as an oil.
[0092] 1H-NMR (CDCl3) delta: 1.22 (3H, t, J=7Hz), 2.59 (2H, t, J=8Hz), 2.93 (2H, t, J=8Hz), 3.14 (4H, s), 4.11 (2H, q, J=7Hz), 7.00 to 7.50 (10H, m) and 7.50 to 7.70 (4H, m).
EXAMPLE 12
3-[2-(4,5-Diphenyl-2-oxazolyl) ethyl]benzenepropanoic acid
[0094] A mixture of ethyl 3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]benzenepropanoate (1.85g, 4.3mmol), 3N sodium hydroxide solution (4.4mL) and methanol (100mL) was heated on a steam bath. After 20 minutes the mixture was concentrated, diluted with water and 1 N hydrochloric acid solution to pH = and extracted with CH2Cl2. The combined extracts were dried over sodium sulfate and the solvent evaporated to leave a white solid. Recrystallization from a mixture of hexanes and CH2Cl2 gave 3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]-benzenepropanoic acid (1.58g, 91%) mp 119-120° C.
[0096] 1H-NMR (CDCl3) delta: 2.64 (2H, t, J = 8Hz), 2.93 (2H, t, J=7Hz), 3.14 (4H, s), 7.05 to 7.50 (10H, m) and 7.50 to 7.75 (4H, m).
EXAMPLE 13
Methyl [3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenoxy]acetate
[0098] Sodium metal (260mg, 11mg atom) was dissolved in methanol (50mL) and dimethyl [(4,5-diphenyl-2-oxazolyl)methyl]phosphonate (3.89g, 11mmol) added followed by methyl (3-formylphenoxy)acetate (2g, 10mmol). The mixture was stirred at room temperature for 20 minutes before being concentrated and diluted with 2N HCI solution. The mixture was extracted with CH2CIz, the organic phase dried over sodium sulfate and the solvent evaported to leave a yellow oil. This was combined with the crude material from a reaction performed on 2g of the phosphonate and 985 mg of aldehyde and chromatographed on a column of silica gel. Elution with a mixture of hexanes and diethyl ether (3:2) furnished methyl [3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenoxy]acetate as the diethyl ether solvate (2.92g, 46%) after recrystallization from diethyl ether, m.p. 79-82 C.
[0099] Anal. Calcd. for C26H21NO4.0.3C4H10O: C, 75.34; H, 5.58; N, 3.23. Found: C, 75.35; H, 5.47; N, 3.17%.
[0100] 1H-NMR (CDCl3) delta: 1.26 (1.25H, t, J=7Hz), 3.53 (0.75 H, q, J=7Hz), 3.88 (3H, s), 4.73 (2H, s), 6.94 (1 H, dd, J = 7.5Hz, J' = 2Hz), 7.06 (1 H, d, J=16Hz), 7.14 (1 H, t, J = 2Hz), 7.20 to 7.55 (8H, m), 7.60 (1 H, d, J = 16Hz), and 7.70 to 7.90 (5H, m).
EXAMPLE 14
[3-[2-(4,5-Diphenyl-2-oxazolyl)ethenyl]phenoxy]acetic Acid
[0102] A mixture of methyl [3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenoxy]acetate (1.00g, 2.5mmol), 5N sodium hydroxide solution (2mL) and methanol (15mL) was heated on a steam bath for 10 minutes before being concentrated. Dilution with water and 2N HCI solution gave a yellow solid which was combined with the crude product from a reaction performed on 1.46g of ester using 3mL of 5N NaOH in 40mL methanol. Recrystallization from ethanol gave [3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenoxy]acetic acid (1.70g, 70%), m.p. 213-215 C.
[0104] 1H-NMR (DMSO-ds) delta: 4.75 (2H, s), 6.90 (1H, m), 7.20 to 7.70 (13H, m) and 13.02 (1H, bs).
EXAMPLE 15
Methyl [4-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenoxy]acetate
[0106] Sodium metal (570mg, 25mg atom) was dissolved in methanol (50mL) and dimethyl [(4,5-diphenyl-2-oxazolyl)methyl]phosphonate (7.80g, 22mmol) added. The mixture was stirred for 10 minutes before adding methyl (4-formylphenoxy)acetate (4.00g, 20mmol). After stirring at room temperature for 1 hour, the mixture was diluted with water and a yellow solid filtered off and air dried to give crude product (3.80g, 44%). This was combined with 3.50g from a previous experiment and recrystallized twice from methanol to afford analytically pure methyl [4-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenoxy]acetate, m.p. 122-123 C.
[0108] H-NMR (DMSO-d6) delta: 3.70 (3H, s), 4.85 (2H, s), 6.97 (2H, d, J=10Hz), 7.08 (1 H, d, J = 13.5Hz), 7.30 to 7.55 (6H, m), and 7.55 to 7.80 (7H, m).
EXAMPLE 16
[4-[2-(4,5-Diphenyl-2-oxazolyl)ethenyl]phenoxy]acetic Acid
[0110] A mixture of methyl [4-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenoxy]acetate (2.00g, 5mmol), 5N sodium hydroxide solution (2.90mL), water (40mL) and methanol (10mL) was heated on a steam bath to give a solution. The mixture was cooled, diluted with 2N hydrochloric acid solution to pH = 1 and filtered. Recrystallization from ethanol gave [4-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]acetic acid (1.34g, 69%), m.p. 223-225 C.
[0112] 1H-NMR (DMSO-d6) delta: 4.74 (2H, s), 6.95 (2H, d, J=8.5Hz), 7.08 (1H, d, J=16Hz), 7.20 to 7.50 (6H, m), 7.50 to 7.70 (5H, m), 7.69 (2H, d, J = 8.5Hz), and 13.08 (1 H, bs).
EXAMPLE 17
Methyl 3-[3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]propanoate
[0114] A mixture of 2-bromomethyl-4,5-diphenyloxazole (10.00g, 3mmol), methyl 3-(3-hydroxyphenyl)-propanoate (5.73g, 3mmol) potassium carbonate (4.83g, 3.5mmol) potassium iodide (catalytic amount) and acetonetrile (150mL) was stirred at reflux temperature. After 30 minutes, the mixture was filtered, concentrated in vacuo and the residual oil chromatographed on a column of silica gel. Elution with a mixture of hexanes and diethyl ether (3:1) furnished methyl 3-[3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]propanoate (10.34g, 78%) as an oil. An analytical sample was prepared by subjecting a 4g sample to chromatography under the conditions described above to furnish pure material as an oil.
[0116] 1H-NMR (CDCl3) delta: 2.63 (2H, t, J=8Hz), 2.95 (2H, t, J=8Hz), 3.65 (3H, s), 5.19 (2H, s), 6.80 to 7.05 (3H, m), 7.20 to 7.55 (7H, m) and 7.60 to 7.80 (4H, m).
EXAMPLE 18
3-[3-[(4,5-Diphenyl-2-oxazolyl)methoxy]phenyl)]propanoic Acid
[0118] A mixture of methyl 3-[3-[(4,5-diphenyl-2-oxazolyl)-methoxy]phenyl]propanoate (6g, 14.5 mmol), 5N sodium hydroxide solution (8.7mL) and methanol (150mL) was heated to reflux on a steam bath. After 20 minutes the mixture was concentrated, diluted with water (200mL) and 2N hydrochloric acid solution to pH = 1. After filtration and drying in air overnight, the solid was recrystallized from a mixture of hexanes and CH2CI2 to give 3-[3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]propanoic acid (4.15g, 71 %), m.p. 118-120 C.
[0119] Anal. Calcd: for C25H21NO4.0.11H2O: C, 74.84; H, 5.33; N, 3.50; H20, 0.45. Found: C, 74.49; H, 5.31; N, 3.31; H20, 0.05%.
[0120] 1H-NMR (CDCl3) delta: 2.67 (2H, t, J=8Hz), 2.95 (2H, t, J=8Hz), 5.22 (2H, s), 6.80 to 7.00 (3H, m), 7.15 to 7.50 (7H, m), 7.55 to 7.80 (4H, m) and 10.71 (1 H, bs).
EXAMPLE 19
[0122] Reaction of 2-bromomethyl-4,5-diphenyloxazole and methyl 3-(4-hydroxyphenyl)propanoate according to the procedure of Example 17 provided the title compound, m.p. 92-95° C.
[0123] Anal. Calcd. for C26H23NO4.0.3H2O: C, 74.56; H, 5.68; N, 3.35; H20, 1.29. Found: C, 74.37; H, 5.81; N, 2.81;H2O, 0.13.
EXAMPLE 20
3-[4-[(4,5-Diphenyl-2-oxazolyl)methoxy]phenyl]propanoic Acid
[0125] Methyl 3-[4-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]propanoate was hydrolyzed with aqueous sodium hydroxide according to the procedure of Example 18 to provide the title compound, m.p. 124-127° C.
EXAMPLE 21
Methyl 3-[3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]-2-propenoate
[0128] Sodium hydride (2.57g of a 60% disp, 64mmol) was washed with hexanes, covered with dimethylether (250mL) and trimethyl phosphonoacetate (10.71g, 9.52mL, 59mmol) added portionwise. The mixture was stirred for 15 minutes and a solution of 3-[(4,5-diphenyl-2-oxazolyl)methoxy]benzaldehyde (19.00g, 53mmol) in dimethylformamide (50mL) added in one portion. The mixture was stirred for 30 minutes to give an amber solution before being diluted with water and extracted with CH2CI2. The combined extracts were dried over sodium sulfate and the solvent evaporated to leave an oil that crystallized upon trituration with a mixture of hexanes and diethyl ether to give methyl 3-[3-(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]-2-propenoate (27.20g, 78%). An analytical sample was prepared by recrystallising 1.40g from iPrOH to give 0.85g of pure material mp 88-90° C.
[0130] 1H-NMR (CDCIa) delta: 3.85 (3H, s), 5.27 (2H, s), 6.49 (1 H, d, J=16Hz), 7.10 to 7.55 (10H, m) and 7.60 to 7.80 (5H, m).
EXAMPLE 22
3-[3-[(4,5-Diphenyl-2-oxazolyl)methoxy]phenyl]-2-propenoic acid
[0132] A mixture of methyl 3-[3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]-2-propenoate (3g, 7.2mmol), 5N sodium hydroxide solution (4.40mL) and methanol (60mL) was heated to reflux. After 30 minutes, the mixture was cooled, concentrated, diluted with water and acidified to pH=1 with 2N hydrochloric acid solution. A yellow solid was filtered off and recyrstallized from a mixture of hexanes and CH2CI2 to give 3-[3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]-2-propenoic acid (2.25g, 77%), mp 145-147 C.
[0133] Anal. calcd. for C25H19NO4.0.1H2O: C, 75.22; H, 4.85; N, 3.51; H20, 0.45. Found: C, 74.94; H, 4.86; N, 3.42;H2O, 0.11%. 1H-NMR (CDCl3/DMSO-d6 ) delta: 5.24 (2H, s), 6.46 (1H, d, J=16Hz), 7.09 (1H, dd, J=8Hz J'=2Hz) 7.17 (1 H, d, J = 8Hz), 7.25 (1 H, d, J = 2Hz), 7.30 to 7.50 (7H, m) and 7.60 to 7.80 (5H, m).
EXAMPLE 23
Methyl 3-[4-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]-2-propenoate
[0135] Reaction of trimethyl phosphonacetate and 4-[(4,5-diphenyl-2-oxazolyl)methoxy]benzaldehyde according to the procedure of Example 21 provided the title compound, m.p. 159-161 ° C.
[0136] Anal. Calcd. for C26H21NO4.0.3N2O: C, 74.92; H, 5.23; N, 3.37; H20, 1.30. Found: C, 74.96; H, 5.04; N, 3.35; H20, 0.03.
EXAMPLE 24
3-[4-(4,5-Diphenyl-2-oxazolyl)methoxy]phenyl]-2-propenoic Acid
[0138] Methyl 3-[4-(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]-2-propenoate was hydrolyzed with aqueous sodium hydroxide according to the procedure of Example 22 to provide the title compound, m.p. 205-207° C.
[0139] Anal. Calcd. for C25H19NO4.0.1H2O: C, 75.22; H, 4.85; N, 3.51; H20, 0.45. Found: C, 75.14; H, 4.86; N, 3.47; H20, 0.20.
EXAMPLE 25
Methyl [3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenoxy]acetate
[0141] A mixture of 2-bromomethyl-4,5-diphenyloxazole (6:68g, 21 mmol), methyl (3-acetoxyphenoxy)acetate (3.87g, 21mmol), potassium carbonate (3.52g, 25mmol), potassium iodide (catalytic amount) and acetonitrile (125mL) was stirred at reflux. After 40 minutes, the mixture was cooled, filtered and the solvent evaporated to leave an oil. Chromatography on a column of silica gel using a mixture of hexanes and diethyl ether (3:1) as eluent furnished hydrated methyl[3-[4,5diphenyl-2-oxazolyl)methoxy]phenoxy]acetate (6.45g, 72%) as an oil.
[0142] Anal. Calcd. for C25H21 NOs.0.2H20: C, 71.66; H, 5.15; N, 3.35; H20, 0.86. Found: C, 71.56; H, 5.49; N, 3.44; H2O, 0.60%.
[0143] 1H-NMR (CDCl3) delta: 3.77 (3H, s), 4.61 (2H, s), 5.17 (2H, s), 6.55 (1 H, dd, J=8Hz J1=2Hz), 6.65 (1 H, m), 6.72 (1 H, dd, J = 8Hz, J' = 2Hz), 7.20 (1 H, t, J = 8Hz), 7.30 to 7.50 (6H, m), and 7.50 to 7.70 (4H, m).
EXAMPLE 26
[3-[(4,5-Diphenyl-2-oxazolyl)methoxy]phenoxy]acetic acid
[0145] A mixture of methyl [3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenoxy acetate (5.85g, 14mmol), 5N sodium hydroxide solution (8.45mL) and methanol (100mL) was heated to reflux. After 10 minutes, the mixture was cooled, the solvent evaporated and the residue diluted with water and 2N HCI solution to pH = 1. A yellow solid was filtered off and recrystallized from a mixture of chloroform, diethyl ether, methanol and hexanes to give hydrated 3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenoxy]acetic acid (2.70g, 47%), mp 133-135 °C.
[0146] Anal. Calcd. for C24H19NO5.0.6H2O: C, 69.93; H, 4.94; H, 3.40; H2O 2.62. Found: C, 69.61; H, 4.79; N, 3.35;H2O, 0.21%.
[0147] 1H-NMR (DMSO-d6) delta: 4.47 (2H, s), 5.29 (2H, s), 6.54 (1 H, d, J =8Hz), 6.68 (2H, m), 7.20 (1 H, t, J = 8Hz), 7.30 to 7.80 (14H, m).
EXAMPLE 27
Ethyl 3-[3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenyl]-2-propenoate
[0149] Reaction of 3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenyltrifluoromethane sulfonate obtained by reaction of trifluoromethanesulfonic anhydride with 3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenol according to the procedure of Example 37 and ethyl acrylate analogously to the procedure of Example 9 provides the title compound.
EXAMPLE 28
3-[3-[2-(4,5-Diphenyl-2-oxazolyl) ethenyl]phenyl]-2-propenoic Acid
[0151] Hydrolysis of ethyl 3-[3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenyl]-2-propenoate with sodium hydroxide analogously to the procedure of Example 10 provides the title compound.
EXAMPLE 29
Methyl [3-[2-[4,5-di(3-thienyl)-2-oxazolyl]ethyl]phenoxy]acetate
[0153] A mixture of 3-[2-[4,5-di(3-thienyl)-2-oxazolyl]ethyl]phenol (2.00g, 5.6mmol), methyl bromoacetate (1.04g, 6.8mmol), potassium carbonate (0.94g, 6.8mmol), potassium iodide (catalytic amount) and acetonitrile (100mL) was stirred at reflux under an atmosphere of nitrogen. After 15 hours, the mixture was cooled, filtered and concentrated and the residue subjected to chromatography on a column of silica gel. Elution with a mixture of hexanes and ethyl acetate (7:2) gave methyl [3-[2-[4,5-di(3-thienyl)-2-oxazolyl]ethyl]-phenoxy]acetate (1.95g, 80%) as an oil.
[0154] Anal. Calcd. for C22H19NO4S2: C, 62.10; H, 4.51; N, 3.30. Found: C, 62.39; H, 4.64; N, 3.37%. 'H-NMR (CDCIa) delta: 3.10 (4H, s), 3.78 (3H, s), 4.60 (2H, s), 6.74 (1H, dd, J=8Hz, J'=2.5Hz), 6.81 (1 H, bs), 6.89 (1 H, d, J = 8Hz), 7.10 to 7.40 (5H, m), and 7.50 to 7.70 (2H, m).
EXAMPLE 30
[3-[2-[4,5-Di(3-thienyl)-2-oxazolyl]ethyl]phenoxy]acetic acid
[0156] A mixture of methyl [3-[2-[4,5-di(3-thienyl)-2-oxazolyl]ethyl]phenoxy]acetate (1.40g, 3.3mmol), 3N sodium hydroxide solution (3.3mL) and methanol (50mL) was heated on a steam bath for 20 minutes. The solvent was evaporated, the residue diluted with water and 1 N HCI solution until pH = and extracted with CH2CI2. The combined extracts were dried over sodium sulfate and concentrated to give a beige solid. Recrystallization from a mixture of hexanes and CH2CI2 (5:3) afforded hydrated [3-[2-[4,5-di(3-thienyl)-2-oxazolyl]ethyl]phenoxy]acetic acid (1.16g, 85%), mp 154-156 °C.
[0157] Anal. Calcd. for C21H17NO4S2.0.4H2O: C, 60.25; H, 4.29; N, 3.35; H20, 1.72. Found: C, 60.11; H, 4.20; N,3.26; H2O,1.06%.
[0158] 1H-NMR (DMSO-d6) delta: 3.06 (4H, m), 4.61 (2H, s), 6.72 (1H, dd, J=8 Hz, J'=2.5 Hz), 6.87 (2H, m), 7.17 (1 H, t, J = 8Hz), 7.25 (2H, m), 7.60 to 7.90 (4H, m) and 13.03 (1 H, bs).
EXAMPLE 31
Methyl [3-[2-[4,5-di(2-thienyl)-2-oxazolyl]ethyl]phenoxy]acetate
[0160] Reaction of 3-[2-[4-5-di(2-thienyl)-2-oxazolyl]ethyl]phenol with methyl bromoacetate according to the procedure of Example 29 provided the title compound.
EXAMPLE 32
[3-[2-[4,5-Di(2-thienyl)-2-oxazolyl]ethyl]phenoxyacetic Acid
[0162] Hydrolysis of methyl [3-[2-[4,5-di(2-thienyl)-2-oxazolyl]ethyl]phenoxy]acetate with aqueous sodium hydroxide provided the hydrated title compound, m.p. 105.5-107° C.
[0163] Anal. Calcd. for C21H17NO4.S2.0.3H2O: C, 60.51; H, 4,26; N, 3.36; H20, 1.29. Found: C, 60.40; H, 4.29; N, 2.95; H2O, 1.26.
EXAMPLE 33
(33-1)
2-Oxo-1,2-diphenylethyl-8-bromooctanoate
[0166] A mixture of benzoin (10g, 47mmol), 8-bromooctanoic acid (11.57g, 52mmol), 1,3-dicyclohexylcarbodiimide (11.66g, 57mmol), 4-dimethylaminopyridine (catalytic amount) and dichloromethane (250mL) was stirred at room temperature under an atmosphere of nitrogen. After 17 hours, the mixture was filtered and concentrated to leave an oil which was chromatographed on a column of silica gel. Eluting with a mixture of hexanes and diethyl ether (9:1) afforded 2-oxo-1,2-diphenylethyl-8-bromooctanoate (18.43g, 93%). A 1 g sample was rechromatographed providing analytically pure material, m.p. 58-62C.
[0168] 1H-NMR (CDCl3) delta: 1.20 to 1.45 (6H, m), 1.67 (2H, quintet, J = 7Hz), 1.82 (2H, quintet, J = 7Hz), 2.46 (2H, m), 3.37 (2H, t, J = 7Hz), 6.86 (1 H, s), 7.30 to 7.55 (8H, m), 7.92 (2H, d, J = 7.5Hz).
(33-2)
2-(7-Bromoheptyl)-4,5-diphenyloxazole
[0170] A solution of 2-oxo-1,2-diphenylethyl-8-bromooctanoate (16.0g, 38mmol), and ammonium acetate (14.8g, 19.2mmol) in acetic acid (240mL) was heated at reflux. After 1 hour, the mixture was poured onto water and extracted with CH2Cl2 (3x). The combined extracts were washed with water, dried over sodium sulfate and concentrated in vacuo to leave an oil. Chromatography on a column of silica gel using a mixture of hexanes and diethyl ether (9:1) as eluent afforded 2-(7-bromoheptyl)-4,5-diphenyloxazole (13.20g, 86%). A 1 g sample was rechromatographed under identical conditions to provide analytically pure material as an oil.
[0172] 1H-NMR (CDCI3) delta: 1.30 to 1.60 (6H, m), 1.80 to 1.95 (4H, m), 2.84 (2H, t, J=7.5Hz), 3.38 (2H, t, J =7Hz), 7.20 to 7.40 (6H, m) and 7.50 to 7.80 (4H, m).
(33-3)
Dimethyl 2-[7-(4,5-diphenyl-2-oxazolyl)heptyl]propanedioate
[0174] A mixture of 2-(7-bromoheptyl)-4,5-diphenyloxazole (10.00g, 25mmol), dimethyl malonate (9.95g, 8.60mL, 75mmol), potassium tert-butoxide (8.44g, 75mmol), Eighteen Crown 6 ether (catalytic amount) and tetrahydrofuran (200mL) was heated to reflux under an atmosphere of nitrogen. After 17.5 hours, the mixture was cooled, diluted with 2N hydrochloric acid solution and extracted with CH2Cl2. The combined extracts were dried over sodium sulfate and concentrated in vacuo to leave an oil. Chromatography on a column of silica gel using a mixture of hexanes and diethyl ether (9:1) as eluent afforded dimethyl 2-[7-(4,5-diphenyl-2-oxazolyl)heptyl]propanedioate (9.47g, 83%) as an oil. An analytical sample (hydrated) was prepared by rechromatographing a 3.28g sample on silica gel using a mixture of hexane and diethyl ether (4:1) as the mobile phase.
[0175] Anal. Calcd. for C27H31 NOs.0.1 HzO: C, 71.86; H, 6.97; N, 3.11; H2O, 0.40. Found: C, .71.70; H, 7.26; N, 3.01; H20, 0.48%.
[0176] 1H-NMR (CDCl3) delta: 1.20 to 1.50 (8H, m), 1.70 to 1.90 (4H, m), 2.80 (2H, t, J = 7.5Hz), 3.33 (1 H, t, J = 7.5Hz), 3.33 (1 H, t, J = 7.5Hz), 3.68 (6H, s); 7.20 to 7.40 (6H, m), and 7.50 to 7.70 (4H, m).
(33-4)
2-[7-(4,5-Diphenyl-2-oxazolyl)heptyl]propanedioic Acid
[0178] A mixture of dimethyl 2-[7-(4,5-diphenyl-2-oxazolyl)heptyl]propanedioate (6.00g, 13mmol), 5N sodium hydroxide solution (13.4mL), water (120mL) and methanol (20mL) was stirred at room temperature. After 10 minutes, the mixture was heated to reflux for 1 hour before adding water (80mL) and 5N NaOH solution (13mL). After a further 3 hours at reflux, the mixture was cooled, acidified with 2N HCI solution and extracted with diethyl ether. The combined extracts were dried over sodium sulphate and the solvent evaporated to leave a white solid, 2-[7-(4,5-diphenyl-2-oxazolyl)heptyl]propanedioic acid (5.65g, 100%). An analytical sample was prepared by recrystallizing 1.15g from a mixture of CH2Cl2, diethyl ether and hexane to give pure product (1.05g), m.p. 115-117" C.
[0180] 1H-NMR (DMSO-d6) delta: 1.10 to 1.45 (8H, m), 1.60 to 1.85 (4H, m), 2.78 (2H, t, J=7.5z), 3.18 (1H, t, J =7.5Hz), 7.25 to 7.50 (6H, m), 7.50 to 7.60 (4H, m) and 12.64 (2H, bs).
EXAMPLE 34
3-[3-Hydroxyphenyl)propionic Acdi
[0184] A solution of 3-hydroxycinnamic acid (20.00g, 122mmol) in methanol (200mL) was hydrogenated over 10% palladium on charcoal (1.25 g) at 45-50 psi using a Parr hydrogenation apparatus. After 4 hours, the mixture was filtered through Celite and the solvent evaporated to leave a tan-colored solid which was used without further purification.
[0185] 1H-NMR (CD30D) delta: 2.32 (2H, t, J = 7.5Hz), 2.68 (2H, t, J = 7.5Hz), 6.30 to 6.50 (3H, m), and 6.82 (1 H, t, J = 8.5Hz).
(34-2)
3-[2-(4,5-Diphenyl-2-oxazolyl)ethyl]phenol
[0187] Sodium metal (2.69g, 0.12g atom) was dissolved in absolute ethanol (250mL) and a solution of 3-(3-hydroxyphenyl)propionic acid (19.38g, 120mmol) in absolute ethanol (125mL) added. The mixture was heated briefly to reflux, cooled and concentrated sulfuric acid (5 drops) in absolute ethanol (5mL) added followed by 2-bromo-2-phenylacetophenone (32.11g, 120mmol). The mixture was stirred a reflux for 5.75 hours, cooled and concentrated in vacuo. To the residue was added glacial acetic acid (600mL) and ammonium acetate (45.09g, 0.58mol) and the mixture heated at reflux for 10.5 hours. The cooled reaction mixture was partitioned between water and CH2CI2, the organic phase separated, washed with water (3x) and saturated NaCl solution. After drying over sodium sulfate, evaporation of the solvent left a golden- colored solid. Recrystallization from a mixture of hexanes and CH2Cl2 (2:1) afforded 3-[2-(4,5-diphenyl)-2-oxazolyl)ethyl]phenol (29.35g, 73%), m.p. 146-147.5° C.
[0188] Anal. Calcd. for C23H19NO2.0.05H2O: C, 80.70; H, 5.63; N, 4.10; H20, 0.26. Found: C, 80.45; H, 5.69; N, 3.92;H2O, 0.11%. 1H-NMR (CDCl3) delta: 3.05 (4H, m), 6.60 (2H, m), 6.68 (1 H, d, J = 7.5Hz), 7.05 (1 H, t, J=7.5Hz), 7.20 to 7.45 (6H, m) and 7.50 to 7.80 (5H, m).
(34-3)
4-[2-(4,5-Diphenyl-2-oxazolyl)ethyl]phenol
[0190] Sodium metal (1.00g, 43mg atom) was dissolved in ethanol (125mL) and 3-(4-hydroxyphenyl)propionic acid (6.04g, 36mmol) added to give a white precipitate. The mixture was warmed briefly with stirring and concentrated H2S04. (3 drops) added followed by 2-bromo-2-phenylacetophenone (1.00g, 36mmol). The mixture was heated at reflux for 2 hours, cooled, concentrated and diluted with water. The mixture was extracted with CH2Cl2, the combined extracts dried over sodium sulfate and concentrated to give an oil which was dissolved in acetic acid (250mL). Ammonium acetate (14.00g, 180mmol) was added and the mixture heated to reflux. After 100 minutes, the solution was cooled, diluted with water and extracted with CH2Cl2. The combined extracts were dried over sodium sulfate and the solvent evaporated to leave a solid that was triturated with a mixture of hexanes and diethyl ether and filtered to give 4-[2-(4-5-diphenyl-2oxazolyl)ethyl]phenol (8.00g, 64%). An analytical sample was prepared by recrystallizing 1.5g from a mixture of hexanes and CH2CIz to give 1.20g of pure material, m.p. 142-1440 C.
[0191] Anal. Calcd. for C23H19NO4.0.1H2O: C, 80.50; H, 5.64; N, 4.04; H20, 0.53. Found: C, 80.16; H, 5.80; N, 4.16; H2O, 0.06%.
[0192] 1H-NMR (CDCl3) delta: 3.30 (4H, m), 6.80 (2H, d, J=8.5Hz), 7.15 (2H, d, J=8.5Hz), 7.35 to 7.70 (6H, m), 7.20 to 7.90 (4H, m) and 7.95 (1 H, bs).
(34-4)
3-[2-(4,5-Diphenyl-2-oxazolyl)ethenyl]phenol
[0194] Sodium metal (1.68g, 73mg atom) was dissolved in ethanol (160mL) and 3-hydroxycinnamic acid (10g, 6mmol) added. After stirring for 5 minutes, concentrated H2S04 (4 drops) was added followed by 2-bromo-2-phenoxyacetophenone (16.76g, 6mmol) and the mixture heated to reflux. After 135 minutes, the mixture was cooled, diluted with water and extracted with CH2Cl2. The combined extracts were dried over sodium sulfate and concentrated to leave an oil which was dissolved in acetic acid (110mL). Ammonium acetate (23.47g, 300mmol) was added and the mixture heated to reflux. After 75 minutes, the solution was cooled, diluted with water and extracted with CH2Cl2. The organic extracts were dried over sodium sulfate and the solvent evaporated to leave a khaki solid that was triturated with diethyl ether to give (10.80g, 52%). Recrystallization of a 1.5g sample from ethanol gave 0.7g of analytically pure 3-[2-(4,5-diphenyl2-oxazolyl)-ethenyl]phenol, m.p. 201-203° C.
[0196] 1H-NMR (DMSO-d6) delta: 6.77 (1 H, d, J=7.5Hz), 7.00 to 7.35 (4H, m), 7.35 to 7.50 (6H, m), 7.53 (1 H, d, J = 16Hz), 7.60 to 7.70 (4H, m), and 9.58 (1 H, s).
EXAMPLE 35
Preparation of Scheme 3 Intermediate Dimethyl[(4,5-diphenyl-2-oxazolyl)methyl]phosponate
[0198] A mixture of 2-bromomethyl-4,5-diphenyloxazole (26.72g, 85mmol) obtained according to D. L. Aldous, et al., J. Org. Chem., 25, 1151 (1960), and trimethylphosphite (80g, 84mL, 645mmol) was heated with stirring at 120°C under an atmosphere of nitrogen. After 90 minutes, the excess trimethyl phosphite was removed in vacuo and the residue chromatographed on a column of silica gel. Elution with a mixture of diethyl ether and methanol (49:1) afforded 6.13g of a yellow solid and 18.90g of an oil with identical TLC characteristics. Recrystallization of 1.3g of the solid material from hexane provided analytically pure dimethyl [(4,5-dimethyl-2-oxazolyl)methyl]phosphonate 1.15g, m.p. 54-57° C.
[0199] Anal. Calcd. for C18H18NO4P: C, 62.98; H, 5.29; N, 4.09. Found: C, 62.88; H, 5.26; N, 4.00%. 1H-NMR (CDCl3) delta: 3.48 (2H, d, J = 21 Hz), 3.81 (6H, d, J = 11 Hz), 7.20 to 7.35 (6H, m) and 7.50 to 7.70 (4H, m).
EXAMPLE 36
[0201] A mixture of 2-bromomethyl-4,5-diphenyloxazole (26.72g, 85mmol) obtained according to D. L. Aldous, et al., J. Org. Chem. 2, 228-334 (1937), 3-hydroxybenzaldehyde (9.34g, 76mmol), potassium carbonate (12.92g, 93mmol), potasssium iodide (0.5g) and dimethylformamide (250mL) was stirred at 110 C. After 45 minutes, the mixture was cooled, diluted with water and extracted with diethyl ether (3x). The combined extracts were washed with water (3x), dried over sodium sulfate and concentrated in vacuo to give an oil which was chromatographed on a column of silica gel. Elution with a mixture of hexanes and diethyl ether (2:1) afforded 3-[(4,5-diphenyl-2-oxazolyl)-methoxy]benzaldehyde (21.16g, 70%). An analytical sample was recrystallized from a mixture of CH2CI2 and hexanes and had mp 72-75° C.
EXAMPLE 37
Preparation of Scheme 5 Intermediate 3-[2-(4,5-Diphenyl-2-oxazolyl) ethyl]phenyltrifluoromethane sulfonate
[0205] Trifluoromethanesulfonic anhydride (16.55g, 58mmol) was added to a stirred solution of 3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenol (10.00g, 29mmol) in pyridine (60mL) maintained at 0°C. The mixture was allowed to stand in the refrigerator overnight before being poured onto ice water and extracted with diethyl ether (3x). The combined extracts were washed four times with water, dried over anhydrous magnesium sulfate and concentrated to leave an oil. Chromatography on a column of silica gel using a mixture of hexanes and ethyl acetate (17:3) gave 3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenyltrifluoromethane sulfonate (12.54g, 90%) as an oil.
[0206] Anal. Calcd. for C24H18F3NO4S: C, 60.89; H, 3.84; N, 2.96. Found: C, 60.97; H, 3.93; N, 3.21%. 1H-NMR (CDCl3) delta: 3.18 (4H, m), 7.10 to 7.50 (10H, m) and 7.50 to 7.70 (4H, m).
EXAMPLE 38
Preparation of Scheme 6 Intermediate Methyl (3-hydroxyphenoxy)acetate
[0208] A mixture of resocirnol monoacetate (20.00g, 0.13mol), methyl bromoacetate (21.14g, 13.05mL, 0.14mol), potassium carbonate (21.80g, 0.16mol) and acetonitrile (350mL) was stirred ar reflux. After 30 minutes, the mixture was filtered, and the solvent removed in vacuo to leave an oil which was dissolved in methanol (350mL). Concentrated hydrochloric acid (2mL) was added and the mixture stirred at reflux. After 20 minutes, the solution was concentrated, diluted with water and extracted with CH2Cl2 to give an oil which was distilled at reduced pressure to furnish, methyl (3-hydroxyphenoxy)acetate, bp 154-180° C/1.5mm (15.98g, 66%).
EXAMPLE 39
Preparation of Scheme 7 Intermediates
(39-1)
2-[2-[3-(Dimethyl(1,1-dimethylethyl) siloxy]phenyl]ethyl]-4,5-di(3-thienyl)oxazole
[0210] n-Butyllithium (0.518g, 8mmol) in hexanes (3.24mL) was added to a solution of diisopropylamine (0.82g, 8mmol) in dry tetrahydrofuran (20mL) maintained at 0°C under an atmosphere of nitrogen. After 20 minutes, the mixture was cooled to -78°C and a solution of 2-methyl-4,5-di(3-thienyl)oxazole (1.60g, 6.5mmol) obtained analogous to D. Davidson, et al., J Org. Chem, 2, 328-334 (1937) in tetrahydrofuran (10mL) added dropwise to give a red-orange solution. The mixture was stirred at -78° C for 2 hours before adding a solution of [3-(bromomethyl)phenoxy]dimethyl(1,1-dimethylethyl)silane (2.44g, 8 mmol) in tetrahydrofuran (5mL). After stirring at -78° C for 4 hours, the mixture was poured onto saturated ammonium chloride solution and extracted with diethyl ether. The combined extracts were washed twice with saturated ammonium chloride solution, once with saturated NaCi solution and dried over magnesium sulfate. The solvent was evaporated and the residue chromatographed on a column of silica gel using a mixture of hexanes and ethyl acetate (19:1) as eluent to give 2-[2-[3-[dimethyl(1-1-dimethylethyl)siloxy]phenyl]ethyl]-4,5-di(3-thienyl)oxazole (1.33g, 43%) as an oil.
[0211] 1H-NMR (CDCI3) delta: 0.14 (6H, s), 0.94 (9H, s), 3.09 (4H, s), 6.70 (2H, m), 6.83 (1H, d, J=8Hz), 7.13 (1 H, t, J = 8Hz), 7.20 to 7.40 (4H, m) and 7.50 to 7.75 (2H, m).
(39-2)
3-[2-[4,5-Di(3-thien 1)-2-oxazolyl]ethyl]phenol
[0213] Tetra-n-butylammonium fluoride (2.98g, 11 mmol) in tetrahydrofuran (11.40mL) was added to a solution of 2-[2-[3-[dimethyl(1,1-dimethylethyl)siloxy]phenyl]ethyl]-4,5-di(3-thienyl)oxazole (4.26g, 9 mmol) in tetrahydrofuran (185 mL). The mixture was stirred at room temperature under an atmosphere of nitrogen. After 30 minutes, the mixture was diluted with diethyl ether and saturated ammonium chloride solution. The organic phase was separated, washed twice with saturated ammonium chloride solution and once with saturated NaCl solution before being dried over sodium sulfate and concentrated in vacuo. Chromatography of the residue on a column of silica using a mixture of hexanes and ethyl acetate (3:1) as eluent gave 3-[2-[4,5-di(3-thienyl)-2-oxazolyl]ethyl]phenol (2.45g, 76%). An analytical sample was prepared by recrystallizing 0.45g from a mixture of hexanes and CH2CI2 (2:1) and had mp 143.5-145° C.
[0214] Anal. Calcd. for C1 9 H1 5NO2S2: C, 64.57; H, 4.28; N, 3.97. Found: C, 64.65; H, 4.41; N, 3.89%. 1H-NMR (DMSO-d6) delta: 3.00 (4H, m), 6.58 (1 H, dd, J=8Hz, J'=2Hz), 6.67 (2H, m), 7.07 (1H, t, J = 8Hz), 7.25 (2H, m), 7.60 to 7.90 (4H, m) and 9.30 (1 H, s).
EXAMPLE 40
5-[[3-[2-(4,5-Diphenyl-2-oxazolyl)ethyl]phenoxy]methyl-1 H-tetrazole
[0216] A mixture of 2-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetonitrile (1.60g, 4.2mmol) and tri-n-butyltin azide (1.45g, 4.4mmol) was stirred at 140°C under an atomosphere of nitrogen. After 20 hours, the mixture was cooled, diluted with ethyl acetate (300mL) and 1 N HCI (200mL) and the mixture stirred for 2 hours. The aqueous phase was removed and the organic phase added to 0.1 M potassium fluoride solution. After stirring overnight, the organic layer was separated, washed with water and saturated sodium chloride solution, dried over sodium sulfate and concentrated in vacuo. The residue was chromatographed on a column of silica gel using a mixture of chloroform and methanol (10:1) as eluent to give 5-[[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]methyl]-1H-tetrazole (1.18g, 66%) after recrystallization from a mixture of hexanes and CH2CI2 m.p. 138.5 - 140°C
[0217] Anal. Calcd. for C25H21 N5O2: C, 70.91; H, 5.00; N, 16.54. Found: C, 70.83; H, 5.05; N, 16.49%. 1H-NMR (CDCl3 + DMSO -d6) delta: 2.91 (4H, s), 5.13 (2H, s), 6.55 to 6.70 (3H, m), 6.90 to 7.20 (7H, m) and 7.30 to 7.50 (4H, m).
SUPPLEMENTAL DISCLOSURE
[0218] The compounds of the instant invention are additionally characterized by Formula (XIX)
wherein n is 7-9 and R is hydrogen or lower alkyl; and Formula (XX)
wherein the OCH2CO2R moiety is attached to the 3 or 4 phenyl position and R is hydrogen or lower alkyl.
[0219] Formula XIX compounds are obtained by a process comprising:
(a) hydrolyzing a compound of Formula XXI
wherein n is 7-9 and Ra is lower alkyl to the corresponding acid, or
(b) esterifying a compound of Formula XXII
wherein n is 7-9 with a lower alkanol, or
(c) alkylating 4,5-diphenyl-2(3H)oxazolethione with Br-(CH2)nCO2Ra wherein n is 7-9 and Ra is lower alkyl.
[0220] Formula XX compounds are obtained by a process comprising:
(a) hydrolyzing a compound of Formula XXIII
wherein R2a is lower alkyl and the OCH2CO2R moiety is attached to the 3 or 4 phenyl position, or
(b) esterifying a compound of Formula XXIV
wherein the OCH2C02H moiety is attached to the 3 or 4 position with a lower alkanol, or
(c) alkylating 4,5-diphenyl-2(3H)-oxazolethione with 3-(bromomethyl)phenoxyacetate or 4-(bromomethyl)-phenoxyacetate.
[0221] The compounds of Formula XIX and Formula XX have pharmacological and pharmaceutical properties similar to those of Formula I and II compounds. In vitro inhibition of human platelet aggregation test result for the compounds of Examples 41-44 are given hereinafter.
EXAMPLE 41
Methyl 8-[(4,5-diphenyl-2-oxazolyl)thio]octanoate
[0223] Sodium hydride (0.71g of a 60% disp., 18 mmol) was added to a stirred solution of 4,5-diphenyl-2(3H)-oxazolethione (4.05g, 16 mmol) in dimethylformamide (50 ml) maintained under a nitrogen atmosphere. The mixture was stirred at room temperature for 15 minutes to give a suspension and methyl 8-bromooctanoate (3.83g, 16 mmol) in DMF (10 mL) added dropwise. After the addition was complete, the reaction mixture was stirred at ambient temperature for 2.5 hours and at 50° C for 30 minutes. The reaction mixture was diluted with Et20 and H20 and stirred. The organic layer was separated, dried (MgSO4) and concentrated to leave an oil which was chromatographed on a column of silica gel. Elution with a mixture of hexanes and diethyl ether (initially 2:1, then 1:1 and finally 1:2) gave methyl 8-[(4,5-diphenyl-2-oxazolyl)thio]octanoate (4.40g, 67.2%) as a partial hydrate.
[0224] Anal. Calcd. for C24H27NO3S. 0.3 H2O: C,69.46; H, 6.70; N, 3.38, Found: C, 69.48; H, 6.88; N, 3.15. 1H-NMR: (CDCl3) delta: 1.26 to 2.33 (10H, m,), 2.30 (2H, t,), 3.24 (2H, t,), 3.66 (3H, s,), 7.31 (6H, m,) and 7.60 (4H, m,).
EXAMPLE 42
8-[(4,5-Diphenyl-2-oxazolyl)thio]octanoic Acid
[0226] Methyl 8-[(4-5-diphenyl-2-oxazolyl)thio]octanoate (2.0 g, 4.9 mmol) was dissolved in methanol (30 mL). A solution of lithium hydroxide monohydrate (0.41 g, 9.8 mmol) in water (8 mL) was added and the mixture heated to reflux for 1 hour. After cooling to room temperature, the methanol was removed in vacuo, the residue diluted with water and acidified to about pH 2 using dilute hydrochloric acid solution. The mixture was extracted with EtOAc, the combined extracts dried over MgS04 and concentrated. The residue was chromatographed on a column of silica gel using CH2Cl2/MeOH (95/5) as eluent to give 8-[(4,5-diphenyl-2-oxazolyl)thio]octanoic acid (1.70 g, 88%).
[0227] Anal. Calcd. for C23H25NO3S. 0.4 HzO: C, 68.59; H, 6.46; N, 3.48. Found: C, 68.84; H, 6.57; N, 3.23. 1H-NMR (CDCIa) delta: 1.27-1.80 (10H, m), 2.26 (2H, t), 3.18 (2H, t), 7.26 (6H, m) and 7.48 (4H, m).
EXAMPLE 43
Methyl [3-[[(4,5-Diphenyl-2-oxazolyl)thio]methyl]phenoxy]acetate
[0229] 4,5-Diphenyl-2(3H)-oxazolethione (5.7 g, 22.8 mmol) was dissolved in DMF (100 mL). Sodium hydride (1.0 g of a 60% dispersion, 25 mmol) was added and the mixture stirred under a nitrogen atmosphere for 30 minutes. The clear solution was cooled to 0 °C and a solution of methyl 3-(bromomethyl)phenoxy acetate (6.5 g, 25 mmol) in DMF (10 mL) added dropwise. After the addition was complete, the suspension was stirred at 0°C for 1 hour and then at room temperature for 2 hours. The reaction mixture was diluted with Et20 and water (200 mL each) and stirred. The organic layer was separated, washed with wter (2 x 20 mL), dried (MgSO4) and concentrated in vacuo. The crude material was purified by flash chromatography on silica gel using a mixture of hexane and diethyl ether (2:1) as eluent to give methyl [3-[[(4,5-diphenyl-2-oxazolyl)thio]methyl]phenoxy]acetate (1.5 g, 13%) as an oil.
[0231] 1H-NMR (CDCl3) delta: 3.75 (3H, s), 4.40 (2H, s), 4.56 (2H, s), 6.78 (1H, dd, J=8Hz, J'=2.5Hz) and 6.98-7.92 (13H, m).
EXAMPLE 44
[3-[[(4,5-Diphenyl-2-oxazolyl)thio]methyl]phenoxy]acetic Acid
[0233] Methyl [3-[[(4-5-diphenyl-2-oxazolyl)thio]methyl]phenoxy]acetate (1.1 g, 2.6 mmol) was dissolved in methanol (25 mL). Lithium hydroxide monohydrate (0.22 g, 5.1 mmol) was added followed by the dropwise addition of water (5 mL). This mixture was heated at reflux for 30 minutes, cooled to room temperature and concentrated in vacuo. The residue was dissolved in water (15 mL) and acidified to about pH 2. The mixture was extracted with methylene chloride (25 mL), the combined extracts dried over MgSO4 and concentrated in vacuo. The residue was purified by chromatography on a column of silica gel using a mixture of CH2Cl2 and MeOH (95:5) as eluent to give [3-[[4,5-diphenyl-2-oxazolyl)thio]methyl]phenoxy]acetic acid (0.6 g, 56.4%), m.p. 136-137° C.
1. A compound of Formula I
where n is 7-9 and R is hydrogen or lower alkyl, and, when R is hydrogen, the alkali metal salts thereof.
where n is 7-9 and R is hydrogen or lower alkyl, and, when R is hydrogen, the alkali metal salts thereof.
2. The compounds of claim 1 which are methyl 4,5-diphenyl-2-oxazolenonanoate; 4,5-diphenyl-2-oxazolenonanoic
acid; methyl 4,5-diphenyl-2-oxazoleoctanoate; and 4,5-diphenyl-2-oxazoleoctanoic acid.
3. A compound of Formula II
wherein
wherein
R1 is phenyl or thienyl;
R2 is hydrogen, lower alkyl or together with CO2 is tetrazol-1-yl;
X is a divalent connecting group selected from the group consisting of CH2CH2, CH=CH, and CH20;
Y is a divalent connecting group attached to the 3 or 4 phenyl position selected from the group consisting of OCH2, CH2CH2 and CH=CH, and, when R2 is hydrogen, the alkali metal salts thereof.
4. The compound of claim 3 wherein R1 is phenyl.
5. The compuond of claim 3 wherein R1 is phenyl, X is CH2CH2 and Y is OCH2.
6. The compounds of claim 3 which are methyl 2-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxylacetate;
2-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetic acid, and the sodium salt thereof;
methyl 2-[4-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenoxy]acetate;
2-[4-[2-(4,5-diphenyl-2-oxazolyl)-ethyl]phenoxy]acetic acid;
ethyl 3-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenyl-2 = propenoate;
3-[3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]phenyl]-2-propenoic acid hydrate hexane solvate;
ethyl 3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]benzenepropanoate;
3-[2-(4,5-diphenyl-2-oxazolyl)ethyl]benzenepropanoic acid;
methyl [3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenoxy]acetate;
[3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenoxy]acetic acid;
methyl [4-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenoxy]acetate;
[4-[2-(4,5-diphenyl-2-oxazolyl)-ethenyl]phenoxy]acetic acid;
methyl 3-[3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]propanoate;
3-[3-[(4,5-diphenyl-2-oxazolyl)-methoxy]phenyl)]propanoic acid;
methyl 3-[4-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]propanoate;
3-[4-[(4,5-diphenyl-2-oxazolyl)-methoxy]phenyl]propanoic acid;
methyl 3-[3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]-2-propenoate;
3-[3-[(4,5-diphenyl-2-oxazolyl)-methoxy]phenyl]-2-propenoic acid;
methyl 3-[4-[(4,5-diphenyl-2-oxazolyl)methoxy]phenyl]-2-propenoate;
3-[4-(4,5-diphenyl-2-oxazolyl)-methoxy]phenyl]-2-propenoic acid;
methyl [3-[(4,5-diphenyl-2-oxazolyl)methoxy]phenoxy]acetate;
[3-[(4,5-diphenyl-2-oxazolyl)-methoxy]phenoxy]acetic acid;
ethyl 3-[3-[2-(4,5-diphenyl-2-oxazolyl)ethenyl]phenyl]-2-propenoate;
methyl [3-[2-[4,5-di(3-thienyl)-2-oxazolyl]ethyl]phenoxy]acetate;
[3-[2-[4,5-di(3-thienyl)-2-oxazolyl]ethyl]phenoxy]acetic acid;
methyl [3-[2-[4,5-di(2-thienyl)-2-oxazolyl]ethyl]phenoxy]acetate;
[3-[2-[4,5-di(2-thienyl)-2-oxazolyl]ethyl]phenoxyacetic acid, and
5-[[3-[2-(4,5-Diphenyl-2-oxazolyl)-ethyl]phenoxy]methyl-1 H-tetrazole.
7. A compound of Formula XIX
wherein n is 7-9 and R is hydrogen or lower alkyl.
wherein n is 7-9 and R is hydrogen or lower alkyl.
8. The compounds of claim 7 which are methyl 8-[(4,5-diphenyl-2-oxazolyl)thio]octanoate,
and
8-[(4,5- diphenyl-2-oxazolyl)thio]octanoic acid.
9. A compound of Formula XX
wherein the OCH2C02R moiety is attached to the 3 or 4 phenyl position and R is hydrogen or lower alkyl.
wherein the OCH2C02R moiety is attached to the 3 or 4 phenyl position and R is hydrogen or lower alkyl.
10. The compounds of claim 9 which are methyl [3-[[(4,5-diphenyl-2-oxazolyl)thio]methyl]phenoxy]acetate,
and
[3-[[(4,5-diphenyl-2-oxazolyl)thio]methyl]phenoxy]acetic acid.
11. The pharmaceutical composition comprising at least one compound according to anyone
of claims 1 to 10 and a pharmaceutical carrier.
12. A process for preparing the pharmaceutical composition of claim 11 which comprises
incorporating at least one compound of claims 1 to 10 to a pharmaceutical carrier.
13. The use of at least one compound according to anyone of claims 1 to 10 for preparing
a pharmaceutical composition for inhibiting blood platelet aggregation.
14. A process for preparing the compounds of claims 1 and 2 of Formula I, comprising
(a) hydrolyzing a compound of Formula la
wherein n is 7-9 and Ra is lower alkyl to the corresponding acid, or
(b) esterifying a compound of Formula lb
wherein n is 7-9 with a lower alkanol, or
(c) reacting a keto ester of Formula III
wherein n is 7-9 and R is hydrogen or lower alkyl with ammonium acetate to form the
corresponding oxazole, or
(d) decarboxylating a substituted malonic acid of Formula IV
wherein n is 6-8.
15. A process for preparing the compounds of claims 3 to 6 of Formula II comprising
(a) hydrolyzing a compound of Formula Ila
wherein R2a is lower alkyl and Ri, X and Y are as defined above to the corresponding acid; or
(b) esterifying a compound of Formula (Ilb)
wherein R1, X and Y are as defined above with a lower alkanol; or
(c) reducing a compound of Formula (III)
wherein R1, R2 and Y are as defined above to provide a compound of Formula (IV)
wherein R1, R2 and Y are as defined above,
(d) alkylating a compound of Formula (V)
wherein R1 and X are as defined above and OH is attached to the 3 or 4 phenyl position with
BrCH2CO2R2a wherein R2a is lower alkyl to provide a compound of Formula (VI)
wherein R2a is lower alkyl, R1 is as defined above, and X is CH2H2, CH=CH; or
(e) alkylating a 3 or 4 substituted phenyl of Formula (VII)
wherein Ya is CH20 or CH2CH2 and R2a is lower alkyl with an oxazole of Formula (VIII)
wherein R1 is phenyl or thienyl to provide a compound of Formula (IX)
wherein R1 and R2 are as defined above and Ya is CH2O or CH2CH2,
(f) reacting the trifluoromethanesulfonate ester of a compound of Formula (X)
wherein R1 is a phenyl or thienyl and OH is attached to the 3 or 4 phenyl position with H2=CHCO2R2a wherein R2a is lower alkyl to provide a compound of Formula (XI)
wherein R1 is phenyl or thienyl and R2a is lower alkyl,
(g) reacting a compound of Formula (XII)
wherein R1 is phenyl and the formyl grouping is attached to the 3 or 4 phenyl position with
the trimethylphosphonate.derivative of CH2CO2R2a wherein R2a is lower alkyl to provide a compound of Formula (XIII)
wherein R1 and R2a are as defined above,
(h) reacting a compound of Formula (XIV)
wherein R2a is lower alkyl and the side chain is attached to the 3 or 4 phenyl position with
a phosphonate oxazole of Formula (XV)
wherein R1 is phenyl or thienyl to provide a compound of Formula (XVI)
wherein R1 is phenyl or thienyl and R2a is lower alkyl,
(i) treating a compound of Formula (XVII)
wherein X and Y are as defined above with tri-n-butyltin azide to provide a tetrazole
of Formula (XVIII)
wherein X and Y are as defined above;
X is a divalent connecting group selected from the group consisting of CH2CH2, CH=CH, and CH20;
Y is a divalent connecting group attached to the 3 or 4 phenyl position selected from the group consisting of OCH2, CH,CH2 and CH=CH.
16. A process for preparing the compounds of claims 7 and 8 of Formula (XIX) comprising
(a) hydrolyzing a compound of Formula XXI
wherein n is 7-9 and Ra is lower alkyl to the corresponding acid, or
(b) esterifying a compound of Formula XXII
wherein n is 7-9 with a lower alkanol, or
(c) alkylating 4,5-diphenyl-2(3H)oxazolethione with Br-(CH2)nCO2Ra wherein n is 7-9 and Ra is lower alkyl.
17. A process for preparing the compounds of claims 9 and 10 of Formula (XX) comprising
(a) hydrolyzing a compound of Formula XXIII
wherein R2a is lower alkyl and the OCH2C02R moiety is attached to the 3 or 4 phenyl position, or
(b) esterifying a compound of Formula XXIV
wherein the OCH2CO2H moiety is attached to the 3 or 4 position with a lower alkanol, or
(c) alkylating 4,5-diphenyl-2(3H)oxazolethione with 3-(bromomethyl)phenoxyacetate or 4-(bromomethyl)phenoxyacetate.